Timeline of Montana history facts for kids

This timeline shares important moments in the history of Montana, a state in the United States.

Montana's Recent History: The 2020s

• 2020
  • November 3: Montana voters chose their leaders. They re-elected Steve Daines as a U.S. Senator. They also elected Matt Rosendale as a U.S. Representative and Greg Gianforte as Governor. The Republicans kept control of the Montana Legislature.
  • April 1: The 2020 United States Census counted Montana's population as about 1,077,000 people. This meant Montana might get a second seat in the U.S. Congress!

Montana in the 2010s

• 2019
  • December 2: Steve Bullock ended his campaign to become President of the United States.
  • January 7: Steve Bullock announced he would run for President of the United States.
• 2017
  • May 25: Greg Gianforte started his job as the U.S. Representative for Montana's at-large congressional district.
• 2015
  • January 3: Steve Daines became the junior U.S. Senator for Montana.
• 2013
  • January 7: Steve Bullock became the 24th governor of Montana.
• 2010
  • April 1: The 2010 United States census counted Montana's population as 989,415. This was a 9.7% increase from 2000. Montana remained the 44th most populated U.S. state.

Montana in the 2000s

• 2009
  • March 30: U.S. President Barack Obama signed a law that created the Pacific Northwest National Scenic Trail and the Ice Age Floods National Geologic Trail. These are special pathways for people to enjoy nature and learn about history.
• 2007
  • January 3: Jon Tester became the junior U.S. Senator for Montana.
• 2005
  • January 3: Brian Schweitzer became the 23rd Governor of Montana.
• 2001
  • January 17: U.S. President Bill Clinton created Pompeys Pillar National Monument and Upper Missouri River Breaks National Monument. These are protected areas with important natural and historical features.
  • January 1: Judy Martz became the 22nd Governor of Montana.
• 2000
  • April 1: The 2000 United States Census counted Montana's population as 902,195. This was a 12.9% increase from 1990. Montana remained the 44th most populated U.S. state.

Montana in the 1990s

• 1995
  • December 9: The United Nations Educational, Scientific and Cultural Organization named Waterton-Glacier International Peace Park a World Heritage Site. This means it's a very special place recognized globally.
• 1993
  • January 4: Marc Racicot became the 21st Governor of Montana.
• 1992
  • October 30: U.S. President George H. W. Bush signed a law that added Big Hole National Battlefield and the Bear Paw Battlefield in Montana to the Nez Perce National Historical Park.
• 1991
  • December 10: U.S. President George H. W. Bush signed a law changing the name of the Custer Battlefield National Monument to the Little Bighorn Battlefield National Monument.
• 1990
  • April 1: The 1990 United States Census counted Montana's population as 786,690. This was a small increase of 1.6% from 1980. Montana remained the 44th most populated U.S. state and lost one of its Congressional districts.

Montana in the 1980s

• 1989
  • January 2: Stan Stephens became the 20th Governor of Montana.
• 1986
  • October 6: U.S. President Ronald Reagan signed a law creating the Nez Perce National Historic Trail. This trail follows the path of the Nez Perce people during their historic journey.
• 1981
  • January 5: Ted Schwinden became the 19th Governor of Montana.
• 1980
  • April 1: The 1980 United States Census counted Montana's population as 786,690. This was a 13.3% increase from 1970. Montana became the 44th most populated U.S. state.

Montana in the 1970s

• 1978
  • November 10: U.S. President Jimmy Carter signed a law that created the Lewis and Clark National Historic Trail and the Continental Divide National Scenic Trail.
  • October 9: UNESCO named Yellowstone National Park one of the first 12 World Heritage Sites.
• 1976
  • July 4: Montana celebrated the 200th birthday of the United States of America.
• 1973
  • January 1: Thomas Lee Judge became the 18th Governor of Montana.
• 1972
  • August 25: U.S. President Richard Nixon signed a law to create the Grant–Kohrs Ranch National Historic Site in Montana. This site preserves a historic ranch.
• 1970
  • April 1: The 1970 United States Census counted Montana's population as 694,409. This was a 2.9% increase from 1960. Montana became the 43rd most populated U.S. state.

Montana in the 1960s

• 1969
  • January 6: Forrest H. Anderson became the 17th Governor of Montana.
• 1968
  • December 2: U.S. President Lyndon B. Johnson signed a law to create the National Trails System. This system helps protect and manage trails across the country.
• 1966
  • October 15: U.S. President Lyndon B. Johnson signed a law to create the Bighorn Canyon National Recreation Area.
  • June 20: The National Park Service established Fort Union Trading Post National Historic Site.
• 1965
  • July 1: The state of Montana changed the name of the Agricultural College of the State of Montana to Montana State University.
• 1963
  • May 17: U.S. President John F. Kennedy signed a law changing the name of the Big Hole Battlefield National Monument to Big Hole National Battlefield.
• 1962
  • January 25: Tim Babcock became the 16th Governor of Montana.
• 1961
  • January 2: Donald Grant Nutter became the 15th Governor of Montana.
• 1960
  • April 1: The 1960 United States Census counted Montana's population as 674,767. This was a 14.2% increase from 1950. Montana became the 41st most populated U.S. state.

Montana in the 1950s

• 1953
  • January 5: J. Hugo Aronson became the 14th Governor of Montana.
• 1950
  • April 1: The 1950 United States Census counted Montana's population as 591,024. This was a 5.6% increase from 1940. Montana became the 42nd most populated U.S. state.

Montana in the 1940s

• 1949
  • January 3: John W. Bonner became the 13th Governor of Montana.
• 1946
  • March 22: The Custer Battlefield National Monument was established.
• 1945
  • September 2: World War II ended when Japan formally surrendered.
  • May 8: The war in Europe ended when Germany formally surrendered.
• 1941
  • December 11: The United States declared war on Germany and Italy.
  • December 8: The United States declared war on Japan and entered World War II.
  • January 6: Sam C. Ford became the 12th Governor of Montana.
• 1940
  • April 1: The 1940 United States Census counted Montana's population as 559,456. This was a 4.1% increase from 1930. Montana remained the 39th most populated U.S. state.

Montana in the 1930s

• 1937
  • August 24: U.S. President Franklin D. Roosevelt signed a law that gave Lewis and Clark Cavern National Monument to the state of Montana. It became Lewis and Clark Caverns State Park.
  • July 22: U.S. President Franklin D. Roosevelt signed the Bankhead-Jones Farm Tenant Act. This law helped farmers and farm families.
  • January 4: Roy E. Ayers became the 11th Governor of Montana.
• 1935
  • December 15: Elmer Holt became the 10th Governor of Montana after Governor Frank Henry Cooney passed away.
• 1933
  • March 13: Frank Henry Cooney became the 9th Governor of Montana after Governor John E. Erickson resigned.
• 1932
  • June 18: The United States and Canada created the Waterton-Glacier International Peace Park. This park crosses the border between the two countries.
• 1930
  • April 1: The 1930 United States Census counted Montana's population as 537,606. This was a small decrease of 2.1% from 1920. Montana remained the 39th most populated U.S. state.

Montana in the 1920s

• 1925
  • January 4: John E. Erickson became the 8th Governor of Montana.
• 1924
  • November 24: The state of Montana created Petroleum County.
  • June 2: U.S. President Calvin Coolidge signed the Indian Citizenship Act of 1924. This law finally gave full U.S. Citizenship to all Native Americans born in the United States.
• 1923
  • May 11: The state of Montana created Lake County.
• 1921
  • January 3: Joseph M. Dixon became the 7th Governor of Montana.
• 1920
  • December 10: The state of Montana created Judith Basin County.
  • October 4: The state of Montana created Golden Valley County.
  • August 30: The state of Montana created Daniels County.
  • April 1: The 1920 United States Census counted Montana's population as 548,889. This was a big increase of 46.0% from 1910. Montana became the 39th most populated U.S. state.
  • February 11: The state of Montana created Liberty County.

Montana in the 1910s

• 1919
  • March 7: The state of Montana created Powder River County.
  • February 20: The state of Montana created McCone County.
  • February 18: The state of Montana created Roosevelt County.
  • February 17: The state of Montana created Glacier County and Pondera County.
  • February 7: The state of Montana created Garfield County and Treasure County.
• 1918
  • November 11: An armistice (a ceasefire) ended World War I.
• 1917
  • April 6: The United States declared war on Germany and entered World War I.
  • February 22: The state of Montana created Carter County and Wheatland County.
• 1916
  • August 25: U.S. President Woodrow Wilson signed a law to establish the National Park Service. This agency manages and protects national parks.
• 1915
  • February 5: The state of Montana created Phillips County and Prairie County.
• 1914
  • August 17: The state of Montana created Wibaux County.
  • August 7: The state of Montana created Mineral County.
  • May 27: The state of Montana created Richland County.
  • May 7: The state of Montana created Toole County.
• 1913
  • December 9: The state of Montana created Fallon County.
  • March 24: The state of Montana created Sheridan County and Stillwater County.
  • January 13: The state of Montana created Big Horn County.
  • January 6: Sam V. Stewart became the 6th Governor of Montana.
• 1912
  • February 29: The state of Montana created Blaine County.
  • February 28: The state of Montana created Hill County.
• 1911
  • February 11: The state of Montana created Musselshell County.
• 1910
  • June 23: U.S. President William Howard Taft created the Big Hole Battlefield National Monument.
  • May 11: U.S. President William Howard Taft signed a law to establish Glacier National Park in Montana.
  • April 1: The 1910 United States Census counted Montana's population as 376,053. This was a huge increase of 54.5% from 1900. Montana became the 40th most populated U.S. state and gained a second Congressional seat.

Montana in the 1900s

• 1909
  • March 9: The state of Montana created Lincoln County.
• 1908
  • July 2: U.S. President Theodore Roosevelt created Jefferson National Forest, Custer National Forest, and Sioux National Forest.
  • July 1: U.S. President Theodore Roosevelt re-established Absaroka National Forest and created Beaverhead National Forest, Deerlodge National Forest, and Bitterroot National Forest.
  • June 30: U.S. President Theodore Roosevelt created Beartooth National Forest.
  • June 25: U.S. President Theodore Roosevelt created Blackfeet National Forest and Flathead National Forest.
  • April 1: Edwin L. Norris became the 5th Governor of Montana.
• 1907
  • March 2: U.S. President Theodore Roosevelt renamed the Lewis & Clarke Forest Reserve to the Lewis & Clark Forest Reserve. He also created the Little Rockies Forest Reserve, the Cabinet Forest Reserve, and the Otter Forest Reserve.
• 1906
  • November 6: U.S. President Theodore Roosevelt created the Little Belt Forest Reserve, the Pryor Mountains Forest Reserve, and the Missoula Forest Reserve.
  • November 5: U.S. President Theodore Roosevelt created the Ekalaka Forest Reserve, the Snowy Mountains Forest Reserve, and the Big Hole Forest Reserve.
  • September 24: U.S. President Theodore Roosevelt created the Long Pine Forest Reserve.
  • September 20: U.S. President Theodore Roosevelt created the Lolo Forest Reserve.
  • August 13: U.S. President Theodore Roosevelt created the Kootenai Forest Reserve.
  • August 10: U.S. President Theodore Roosevelt created the Crazy Mountains Forest Reserve.
  • June 8: U.S. President Theodore Roosevelt signed the Antiquities Act of 1906. This law gave the President the power to create national monuments on federal lands to protect important natural, cultural, or scientific places.
  • April 12: U.S. President Theodore Roosevelt created the Helena Forest Reserve.
• 1905
  • October 3: U.S. President Theodore Roosevelt created the Big Belt Forest Reserve, the Hell Gate Forest Reserve, and the Little Belt Forest Reserve.
  • May 12: U.S. President Theodore Roosevelt created the Elkhorn Forest Reserve.
  • February 7: The state of Montana created Sanders County.
• 1904
  • June 14: U.S. President Theodore Roosevelt created the Bitter Root Forest Reserve.
• 1903
  • January 29: U.S. President Theodore Roosevelt created the Highwood Mountains Forest Reserve.
  • January 29: U.S. President Theodore Roosevelt combined the Absaroka Forest Reserve into the Yellowstone Forest Reserve.
• 1902
  • September 4: U.S. President Theodore Roosevelt created the Absaroka Forest Reserve.
  • August 16: U.S. President Theodore Roosevelt created the Little Belt Mountains Forest Reserve and the Madison Forest Reserve.
• 1901
  • February 11: The state of Montana created Rosebud County.
  • January 31: The state of Montana created Powell County.
  • January 7: Joseph Toole became the 4th Governor of Montana.
• 1900
  • April 1: The 1900 United States Census counted Montana's population as 243,329. This was a big increase of 70.3% from 1890. Montana became the 41st most populated U.S. state.

Montana in the 1890s

• 1899
  • February 10: U.S. President Grover Cleveland created the Gallatin Forest Reserve.
• 1898
  • December 10: The United States and Spain signed the Treaty of Paris to end the Spanish–American War.
  • August 12: The United States and Spain signed a peace agreement.
  • April 23: Spain declared war on the United States. The U.S. declared war on Spain two days later.
• 1897
  • February 22: U.S. President Grover Cleveland created the Bitter Root Forest Reserve, the Lewis & Clarke Forest Reserve, and the Flathead Forest Reserve.
  • February 9: The state of Montana created Broadwater County.
  • January 4: Robert Burns Smith became the 3rd Governor of Montana.
• 1895
  • March 5: The state of Montana created Sweet Grass County.
  • March 4: The state of Montana created Carbon County.
• 1893
  • March 2: The state of Montana created Granite County.
  • February 16: The state of Montana created Ravalli County.
  • February 16: The state of Montana founded the Agricultural College of the State of Montana.
  • February 13: The state of Montana founded the University of Montana.
  • February 7: The state of Montana created Teton County.
  • February 6: The state of Montana created Flathead County and Valley County.
  • January 2: John E. Rickards became the 2nd Governor of Montana.
• 1891
  • March 3: U.S. President Benjamin Harrison signed the Forest Reserve Act of 1891. This law gave the President the power to create protected national forests on federal lands.
• 1890
  • April 1: The 1890 United States Census counted the population of Montana as 142,924. This was a huge increase of 265.0% from 1880. Montana became the 41st most populated U.S. state.

Montana in the 1880s

• 1889
  • November 8: Joseph Toole became the 1st Governor of Montana.
  • November 8: U.S. President Benjamin Harrison officially declared Montana a state. The Territory of Montana became the State of Montana, the 41st U.S. state!
  • April 9: U.S. President Benjamin Harrison appointed Benjamin F. White as the 9th (and last) Governor of the Territory of Montana.
  • February 22: U.S. President Grover Cleveland signed a law that allowed the people of Montana (and other territories) to create their own state governments and join the Union.
• 1887
  • September 12: The Territory of Montana created Cascade County.
  • February 23: The Territory of Montana created Park County.
  • February 8: U.S. President Grover Cleveland appointed Preston Leslie as the 8th Governor of the Territory of Montana.
• 1885
  • July 14: U.S. President Grover Cleveland appointed Samuel Thomas Hauser as the 7th Governor of the Territory of Montana.
  • March 12: The Territory of Montana created Fergus County.
• 1884
  • December 16: U.S. President Chester A. Arthur appointed B. Platt Carpenter as the 6th Governor of the Territory of Montana.
• 1883
  • July 13: U.S. President Chester A. Arthur appointed John Schuyler Crosby as the 5th Governor of the Territory of Montana.
  • February 26: The Territory of Montana created Yellowstone County.
• 1881
  • February 16: The Territory of Montana created Silver Bow County.
• 1880
  • April 1: The 1880 United States Census counted the population of the Territory of Montana as 39,159. This was a 90.1% increase from 1870. Montana became the 6th most populated U.S. territory.

Montana in the 1870s

• 1877
  • September 30: U.S. soldiers attacked Nez Perce people led by Chief Joseph who were trying to escape to Canada in the Battle of Bear Paw. Chief Joseph and many Nez Perce were captured.
  • September 13: U.S. soldiers attacked Nez Perce people trying to escape to Canada in the Battle of Canyon Creek.
  • August 9: U.S. soldiers attacked Nez Perce people in the Bitterroot Valley in the Battle of the Big Hole.
  • February 16: The Territory of Montana changed the name of Big Horn County to Custer County to honor George Armstrong Custer.
• 1876
  • July 4: Montana celebrated the 100th birthday of the United States, even though the state was still dealing with the aftermath of the Battle of the Little Bighorn.
  • June 26: The 7th Cavalry Regiment led by George Armstrong Custer was defeated at the Battle of the Little Bighorn by Lakota, Northern Cheyenne, and Arapaho warriors.
• 1875
  • April 19: The Territory of Montana chose Helena as its third capital city. Helena is still the capital of Montana today.
• 1872
  • March 1: U.S. President Ulysses S. Grant signed a law creating Yellowstone National Park, the world's first national park!
• 1870
  • July 13: U.S. President Ulysses S. Grant appointed Benjamin F. Potts as the 4th Governor of the Territory of Montana.
  • April 1: The 1870 United States Census counted the population of the Territory of Montana as 20,595. Montana was the 6th most populated U.S. territory.

Montana in the 1860s

• 1869
  • April 9: U.S. President Ulysses S. Grant appointed James Mitchell Ashley as the 3rd Governor of the Territory of Montana.
  • January 15: The Territory of Montana created Dawson County.
• 1868
  • March 1: The Territory of Montana changed the name of Edgerton County to Lewis and Clark County to honor Meriwether Lewis and William Clark.
• 1867
  • November 16: The Territory of Montana created Meagher County.
• 1866
  • October 3: U.S. President Andrew Johnson appointed Green Clay Smith as the 2nd Governor of the Territory of Montana.
• 1865
  • February 7: The Territory of Montana chose Virginia City as its second capital city.
  • February 2: The Territory of Montana created nine original counties: Beaverhead County, Big Horn County, Chouteau County, Deer Lodge County, Edgerton County, Gallatin County, Jefferson County, Madison County, and Missoula County.
• 1864
  • October 30: The gold mining camp of Helena was established.
  • September: Sidney Edgerton arrived in Bannack, the first Territorial Governor of Montana.
  • July 14: Four miners from Georgia discovered gold at Last Chance Gulch.
  • June 22: U.S. President Abraham Lincoln appointed Sidney Edgerton as the 1st Governor of the Territory of Montana.
  • May 28: The provisional Montana Territorial Legislature chose Bannack as the first capital city.
  • May 26: U.S. President Abraham Lincoln signed a law to create the Territory of Montana.
• 1863
  • June 16: The Virginia City Mining District was established in the Idaho Territory.
  • May 26: Bill Fairweather and Henry Edgar discovered gold along Alder Creek in the Idaho Territory.
  • March 3: U.S. President Abraham Lincoln signed a law to create the Idaho Territory. This territory included all of the future state of Montana.
• 1862
  • July 28: Gold was discovered along Grasshopper Creek in the Dakota Territory. Bannack City was established nearby.
• 1861
  • April 12: The American Civil War began with the Battle of Fort Sumter.
  • March 4: Abraham Lincoln became the 16th President of the United States.
  • March 2: U.S. President James Buchanan signed a law to create the Dakota Territory. This territory included all of the future state of Montana east of the Continental Divide of the Americas.
  • February 8: Seven southern states that allowed slavery created the Confederate States of America.
• 1860
  • November 6: Abraham Lincoln was elected President of the United States. Seven states would leave the United States before February 1861.
  • July 2: Steamboats arrived at Fort Benton, Montana, the furthest point up the Missouri River that boats could travel.
  • The United States Government completed the Mullan Road between Fort Benton and Walla Walla, Washington.
  • Francis Lyman Worden and Captain Christopher P. Higgins founded the settlement of Hell Gate near where Missoula, Montana would later be.

Montana in the 1850s

• 1858
  • May 12: Brothers James and Granville Stuart discovered gold at Gold Creek near where Drummond, Montana would later be.
• 1855
  • July 16: Isaac Stevens, the first Governor of the Washington Territory, made a treaty with Salish, Pend d'Oreille, and Kootenai chiefs. This treaty established the Jocko Reservation.
• 1854
  • May 30: U.S. President Franklin Pierce signed a law to organize the Territories of Nebraska and Kansas. The Nebraska Territory included all of the future state of Montana east of the Continental Divide of the Americas.
• 1853
  • March 2: U.S. President Millard Fillmore signed a law to establish the Washington Territory. This territory included the part of the future state of Montana west of the Continental Divide of the Americas. The rest of the future state was still unorganized U.S. territory.
• 1852
  • Summer: Trapper Francois Finlay discovered gold flakes in Benetsee Creek (later called Gold Creek) in the Oregon Territory.

Montana in the 1840s

• 1848
  • August 14: U.S. President James K. Polk signed a law to establish the Oregon Territory. This territory included the part of the future state of Montana west of the Continental Divide of the Americas. The rest of the future state was still unorganized U.S. territory.
  • February 2: The United States and Mexico signed the Treaty of Guadalupe Hidalgo to end the Mexican–American War.
• 1846
  • July 17: The Oregon Treaty between the United States and Great Britain took effect. This treaty set the 49th parallel north as the international border, meaning all land in the future state of Montana became unorganized U.S. territory.
  • May 13: The United States declared war on Mexico.
  • Alexander Culbertson established Fort Benton, the last fur trading post on the Upper Missouri River.
• 1841
  • September 24: French Jesuit priest Pierre-Jean De Smet arrived in the Bitterroot Valley and established St. Mary's Mission. This was the first European-American settlement in the future state of Montana.

Montana in the 1830s

• 1832
  • Spring: The steamboat Yellowstone made its first trip from St. Louis to Fort Union and back.

Montana in the 1820s

• 1828
  • Spring: The American Fur Company established Fort Union on the Missouri River where it meets the Yellowstone River.
• 1822
  • March 10: William Henry Ashley formed the Rocky Mountain Fur Company in St. Louis. This company operated in Wyoming and Montana for twelve years. Famous trappers like Jim Bridger, William Sublette, and Jedediah Smith worked for the company.
• 1821
  • August 10: The State of Missouri joined the United States. The rest of the Missouri Territory became unorganized U.S. territory.
  • March 2: U.S. President James Monroe signed a law allowing the people of the Missouri territory to form a state government.

Montana in the 1810s

• 1819
  • January 30: The Treaty of 1818 between the United States and Great Britain took effect. This treaty divided the future state of Montana between the Oregon Country (west of the Continental Divide) and the Missouri Territory (east of the Continental Divide).
• 1814
  • William Clark published '.
• 1812
  • October 1: The Missouri Territory created St. Charles County, which included all land in the future state of Montana in the Missouri River watershed.
  • June 4: U.S. President James Madison signed a law for the government of the Missouri Territory. The Louisiana Territory was renamed the Missouri Territory. This territory included all land in the future state of Montana in the Missouri River watershed.
• 1810
  • February 26: Canadian fur trader and explorer David Thompson met Salish Indians wintering on the Flathead River below Flathead Lake.

Montana in the 1800s

• 1809
  • November 9: Canadian fur trader and explorer David Thompson established Saleesh House at Thompson Falls on the Columbia River.
• 1807
  • November 21: Fur trader Manuel Lisa established Fort Raymond where the Big Horn River meets the Yellowstone River.
• 1806
  • September 23: The Lewis and Clark Expedition arrived back in St. Louis.
  • August 11: The Lewis and Clark Expedition reunited where the Yellowstone River meets the Missouri River.
  • July 7: William Clark and other members of the Lewis and Clark Expedition crossed the Continental Divide of the Americas at Big Hole Pass.
  • July 7: Meriwether Lewis and nine other members of the Lewis and Clark Expedition crossed the Continental Divide of the Americas at Lewis and Clark Pass.
  • July 3: On their way back east, Meriwether Lewis and William Clark decided to split their expedition to find a shorter route to the Missouri River.
  • March 22: The Lewis and Clark Expedition left Fort Clatsop and began their journey back to the United States.
• 1805
  • December 7: The Lewis and Clark Expedition arrived at their winter camp on the Columbia River and began building Fort Clatsop.
  • August 12: Meriwether Lewis and three other members of the Lewis and Clark Expedition crossed the Continental Divide of the Americas at Lemhi Pass. They entered land claimed by Native Americans, Spain, Great Britain, and Russia. The rest of the expedition followed.
  • June 13: The Lewis and Clark Expedition reached the Great Falls of the Missouri River. It took them four weeks to carry their boats and supplies around the falls.
  • April: The Lewis and Clark Expedition traveled up the Missouri River and entered the future state of Montana.
  • March 3: U.S. President Thomas Jefferson signed a law to reorganize the District of Louisiana as the self-governing Louisiana Territory. This territory included all land in the future state of Montana in the Missouri River watershed.
• 1804
  • October 1: The District of Louisiana was organized under the control of the Indiana Territory.
  • May 21: The Lewis and Clark Expedition left St. Charles and began their journey up the Missouri River.
  • March 26: U.S. President Thomas Jefferson signed a law dividing Louisiana into two territories. The northern part was called the military District of Louisiana.
• 1803
  • December 20: France handed over its colony of Louisiana to the United States. All land in the future state of Montana in the Missouri River watershed became unorganized U.S. territory.
  • April 30: The United States and France signed the Louisiana Purchase Treaty.
• 1800
  • October 1: Spain secretly transferred the colony of Louisiana back to France.

Montana in the 1780s

• 1783
  • September 3: The Treaty of Paris was signed. This treaty confirmed the independence of the United States and set the Mississippi River as its western border.

Montana in the 1770s

• 1776
  • July 4: Representatives of the thirteen United States signed the Declaration of Independence from Great Britain.

Montana in the 1760s

• 1762
  • November 13: France secretly transferred its colony of Louisiana to Spain. France was worried about losing its American lands in the Seven Years' War.

Montana in the 1680s

• 1682
  • April 9: René-Robert Cavelier, Sieur de La Salle, claimed the Mississippi River and all the land it drained for France. He named the region Louisiana. This claim included all land in the future state of Montana east of the Continental Divide of the Americas. This led to competition among Native American peoples, France, Spain, and later the United States for control of the area.

Montana in the 1540s

• 1541
  • June 28: A Spanish military group led by Hernando de Soto became the first Europeans to cross the Mississippi River.

Montana in the 1510s

• 1513
  • September 29: Spanish explorer Vasco Núñez de Balboa crossed the Isthmus of Panama and reached the Pacific Ocean. He claimed the ocean and all nearby lands for the Queen of Castile. This claim included the part of the future state of Montana west of the Continental Divide of the Americas.

Montana in the 1490s

• 1493
  • May 5: Pope Alexander VI issued a special order that divided the non-Christian world into two halves. The western half, including all of North America, went to the Queen of Castile and the King of Aragon for exploration and conquest. The indigenous peoples of the Americas living there had no idea this was happening.
• 1492
  • October 12: Christopher Columbus landed on an island in the Caribbean. This marked the beginning of Spanish exploration and conquest in the Americas.

Before 1492

• Around 12,000 BCE
  • During a long period of warming, Paleoamericans from Beringia (a land bridge that once connected Asia and North America) began using an ice-free path east of the Rocky Mountains. They used this path to travel and settle throughout the Americas.